Whole genome sequencing of macrolide resistant Streptococcus pneumoniae serotype 19A sequence type 416
Abstract Background: The resistance of Streptococcus pneumoniae to macrolides is becoming an increasingly important issue and thus it is important to understand the genetics related to adaptation of this species to the widespread use of antibiotics in Europe. The 58 isolates of S. pneumoniae belonging to sequence type 416 and serotype 19A and to several different phenotypes originated from Italy, Portugal and Czech Republic were thus sequenced on Illumina MiSeq. The aim of the study was to describe the relation between isolates in this collection and the Netherlands15B-37 clone, which belongs to serotype 15B and sequence type 199. The association of sequence type 416 with macrolide resistance was also investigated. Results: Investigation of genes associated with serotype confirmed common recent origin of inquired isolates in the serotype switch between 15B and 19A serotypes. The genes associated with the macrolide resistance are to be quite variable even within closely genetically relative isolates. Conclusions: This tendency to interchange and modification of genes associated with macrolide resistance and surrounding sequences could lead to adaptation to different circumstances and thus to accelerate spreading of this sequence type in regions with high macrolide consumption.